(1D + 1D) approach mathematical modeling of two phase multicomponent transport flow in PEMFC

A quasi two dimensional (1D + 1D), multi-component model is developed in order to analyze the two-phase transport in polymer electrolyte fuel cell. Different operating parameters, including temperature and wettability are examined and their effects are discussed. The present simple and easy to implement model can be as accurate as a complete two dimensional model. Furthermore, it is seen that the simplification made in this model reduce the computational time.     

Wafer-scale mitochondrial membrane potential assays

It has been reported that mitochondrial metabolic and biophysical parameters are associated with degenerative diseases and the aging process. To evaluate these biochemical parameters, current technology requires several hundred milligrams of isolated mitochondria for functional assays. Here, we demonstrate manufacturable wafer-scale mitochondrial functional assay lab-on-a-chip devices, which require mitochondrial protein quantities three orders of magnitude less than current assays, integrated onto 4' standard silicon wafer with new fabrication processes and materials. Membrane potential changes of isolated mitochondria from various well-established cell lines such as human HeLa cell line (Heb7A), human osteosarcoma cell line (143b) and mouse skeletal muscle tissue were investigated and compared. This second generation integrated lab-on-a-chip system developed here shows enhanced structural durability and reproducibility while increasing the sensitivity to changes in mitochondrial membrane potential by an order of magnitude as compared to first generation technologies. We envision this system to be a great candidate to substitute current mitochondrial assay systems.     

Vibrational analysis of electrostatically actuated microstructures considering nonlinear effects

The vibrational behavior of electrostatically actuated microstructures subjected to nonlinear squeeze film damping and in-plane forces is investigated. First-Order Shear Deformation Theory is used to model dynamical system by means of finite element method, while finite difference method is applied to solve the nonlinear Reynolds equation of squeeze film damping simultaneously. Vibrational analysis of microplates is performed by solving eigenvalue problem, after validating the model by pull-in phenomenon and transient behavior. In addition, considering nonlinear squeeze film damping and step-input actuations, response frequencies of microplates are calculated. Effect of ambient pressure and in-plane forces on dynamic pull-in phenomenon is also studied. Results for simplified models are verified and are in good agreement with the published literature. This investigation can reveal nonlinear vibrational behavior of microstructures.     

Preparation and characterization of ZnO nanocrystallines in the presence of an ionic liquid using microwave irradiation and photocatalytic activity

Fast, simple and template-free method is proposed for preparation of ZnO nanocrystallines in the presence of 1-ethyl-3- methylimidazolium ethyl sulfate, [EMIM][EtSO₄], a room-temperature ionic liquid (RTIL) under microwave irradiation. The powder X-ray diffraction (XRD) studies display that products are excellently crystallized in the form of wurtzite hexagonal structure. Energy dispersive X-ray spectroscopy (EDX) investigations reveal that the products are extremely pure. The results obtained by scanning electron microscopy (SEM) demonstrate that mean size of ZnO nanocrystallines decreases with microwave irradiation time and the RTIL content of media. Diffuse reflectance spectra (DRS) of the ZnO nanocrystallines shows blue shift relative to the bulk ZnO, which can be attributed to quantum confinement effect of ZnO nanocrystallines. A possible formation mechanism of the ZnO nanocrystallines in aqueous solution of the RTIL is presented. Photocatalytic activity of the ZnO nanocrystallines towards photodegradation of methylene blue (MB) was carried out. The results demonstrate that photocatalytic activity of the ZnO nanocrystallines increases with microwave irradiation time and the RTIL content of media.     

A facile route to functionalized 1-arylsulfonyl-1,2-dihydroquinolines

Summary A one-pot synthesis of dialkyl 1-arylsulfonyl-1,2-dihydroquinoline-2,3-dicarboxylates by reaction of arylsulfonamide derivatives of 2-aminobenzaldehyde, dialkyl acetylenedicarboxylates, and triphenylphosphine in excellent yields is reported.

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Ein einfacher Weg zu funktionalisierten 1-Arylsulfonyl-1,2-dihydrochinolinen

Zusammenfassung Es wird über eine Eintopfsynthese zur Herstellung von Dialkyl-1-arylsulfonyl-1,2-dihydrochinolin-2,3-dicarboxylaten durch Umsetzung von Arylsulfonamid berichtet. Die Reaktion liefert ausgezeichnete Ausbeuten.

     

Electrochemical study on the natural and chemical preservatives antibacterial effect against S. aureus PTCC 1112 and its determination at low levels

Journal of the Iranian Chemical Society - Pathogen microorganisms detection, such as Staphylococcus aureus (S. aureus), is so critical because it can be dangerous for public health. In this...     

Synthesis of 5‐Aryl‐3‐(methylsulfanyl)‐1H‐pyrazoles via Three‐Component Reaction of 1,1‐Bis(methylsulfanyl)‐2‐nitroethene,Aromatic Aldehydes,and Hydrazine

An efficient approach for the preparation of functionalized 5‐aryl‐3‐(methylsulfanyl)‐1H‐pyrazoles 2 is described. This three‐component reaction between benzaldehydes 1 , NH₂NH₂?H₂O, and 1,1‐bis(methylsulfanyl)‐2‐nitroethene proceeds in EtOH under reflux conditions in good‐to‐excellent yields. The structures of 2 were corroborated spectroscopically (IR, ¹H‐ and ¹³C‐NMR, and EI‐MS). A plausible mechanism for this type of reaction is proposed (Scheme 2).     

A green approach for the electrochemical synthesis of 4-morpholino-2-(arylsulfonyl)benzenamines

Electrochemical synthesis of 4-morpholino-2-arylsulfonyl-benzamines was carried out by the electrochemical oxidation of 4-morpholinoaniline in the presence of arenesulfinic acids at a carbon electrode, in aqueous solution. Our voltammetric data indicate that electrochemically generated p-quinone-diimine participates in Michael type addition reaction with arenesulfinic acids and via an EC mechanism converts to the title products. This method provides a green, one-pot procedure for the synthesis of 4-morpholino-2-(arylsulfonyl)benzenamines of potential biological significance.     

Electrophoretic mobility for peptides with post-translational modifications in capillary electrophoresis

Several semiempirical models for peptide electrophoretic mobility have been tested for capillary electrophoresis (CE) separation with a positively charged capillary using on-line CE combined with electrospray ionization-mass spectrometry (ESI-MS). In the current system with pH 2.7, the expression q/M(0.56) provided the best correlation with the electrophoretic mobility in the analysis of a set of 18 standard samples, where q is the calculated net charge and M is the molecular weight. The peptides resulting from various digests of horse heart myoglobin or bovine hemoglobin were used to demonstrate the validity of this correlation. Post-translationally modified peptides from tryptic digest of human myelin basic protein were also investigated and were found to provide excellent correlation with the linear plot when the total charge of the peptide was correctly calculated. If the total charge was not properly calculated then the post-translationally modified peptides fell off the linear plot. Using this method five arginine residues (residues 5, 49, 54, 97 and 130) were found to be partially citrullinated, four glutamine residues (residues 8, 103, 121 and 147) were found to be partially deamidated and both methionines at residues 21 and 167 were found to be partially oxidized. Three peptides were found with phosphorylation; TPPPSQGK (residue 98 to 105), FSWGAEGQR (residue 114 to 122), and SGSPMAR (residue 163 to 169) and Arginine at 107 was found to be partially monomethylated or dimethylated. The method may provide an excellent means of identifying the presence of peptides with post-translational modifications in conjunction with MS.     

One-pot synthesis of stable phosphonium ylides using 2-aminothiophenol

Protonation of reactive 1:1 intermediates produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylate by 2-aminothiophenol leads to vinylphosphonium salts, which undergo Michael addition with thiophenolate anion to produce highly functionalized phosphonium ylides in excellent yields.